首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12篇
  免费   0篇
林业   3篇
  4篇
农作物   1篇
畜牧兽医   3篇
植物保护   1篇
  2021年   1篇
  2019年   1篇
  2016年   2篇
  2013年   1篇
  2012年   1篇
  2011年   1篇
  2010年   1篇
  2008年   2篇
  2005年   2篇
排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
Individuals were selected for resistance against the imperfect fungus Seiridium cardinale Wag in six common cypress populations (Cupressus sempervirens L.) in Greece. A total of 109 resistant clones and 140 trees from their base populations were surveyed at several allozyme loci. The comparison yielded information on changes in genetic variation due to artificial selection. The genetic structure of the breeding populations was similar to their base populations. Nevertheless, the number of rare alleles among the resistant clones had decreased, showing a similar trend at most loci and for most comparisons. Possible implications for breeding strategies are discussed.  相似文献   
2.
In the present study, we report on the changes observed in the kinetic properties of pyruvate kinase (PK) from whole body homogenate in the three developmental stages of the insect Tenebrio molitor after insecticide or acetone injection, and after injury and 24 h starvation. The apparent Km value of the enzyme towards phosphoenolpyruvate was higher in the pupae stage than in the rest developmental stages although the same enzyme type appears to be present throughout the life span of the insect as judged by its Vmax and sensitivity towards ATP and Alanine. The highest specific activity, twice as high as that of larvae and pupae, was observed in adults. Starvation resulted to activation of the enzyme by increasing the Km value in the two feeding stages, namely larvae and adult, while injury had the opposite effect. Acetone injection did not have any significant effect at any stage. Insecticide injection had varying effects, depending upon the developmental stage, the dose and the type of the insecticide. In larvae, low doses of methyl paraoxon and methyl parathion activated the enzyme but as the dose increased the Km value returned to normal levels. Low dose of decamethrin activated the enzyme also but at high dose it caused a severe inactivation as judged by a fivefold increase of the observed Km. In pupae, decamethrin had no effect, methyl parathion had similar effects to those observed in larvae, and methyl paraoxon caused activation of the enzyme at any dose given. In the adult stage none of the injected insecticides had any effect on the Km value although Vmax and specific activity were significantly altered.  相似文献   
3.
Strawberry plants are relatively unresponsive to nitrogen (N) fertilization. Supraoptimal N application also results in excessive vegetative growth, which competes to reproductive growth. Two strawberry field experiments were conducted for two consecutive years using fertigation to investigate the effect of different nitrogen (N) application rates on yield and growth of an everbearing strawberry (cv. Evie II). N was injected weekly into the drip irrigation system at 0, 0.5, 1, 3, and 6 kg N/ha/week the first year and 0, 1, 2, and 3 kg N/ha/week the next year. Fruit yield and fruit number were not affected the first year, but were increased the second year due to N application. However, there was no effect of N nutrition on average berry weight for both years. It was concluded that N fertilization may increase yield and fruit number, but average berry weight remains unaffected.  相似文献   
4.
Two greenhouse pot experiments were conducted in Agrinion, Greece, using a randomized block design in four replications, respectively, as follows: The first one included five levels of treated municipal wastewater (TMWW), being used as an irrigation water source. The second one, five levels of applied Cl at a constant soil applied Cd level of 10.36?mg/kg soil, the plants being irrigated with fresh well water. The purpose of these experiments was to study the impact of the Cl ?? Cd interrelationship on planning TMWW reuse, for the irrigation of Brassica oleracea var. Capitata (cabbage) cv F1 Gloria, ehich was used as test plant, in both of these experiments. It was found that the TMWW Cl content, originating mainly from the procedure of wastewater chlorination, was synergistically interrelated with the toxic heavy metal Cd, increasing its soil availability and cabbage plant leaf uptake (edible plant part). As this increase is directly associated with the consumer??s health, it was suggested that the TMWW be subjected to dechlorination process or the disinfection be made by ozonation or UV, which do not include Cl.  相似文献   
5.
With the problem of parasitic nematode drug resistance increasing, vaccine development offers an alternative sustainable control approach. For some parasitic nematodes, native extracts enriched for specific proteins are highly protective. However, recombinant forms of these proteins have failed to replicate this protection. This is thought to be due to differences in glycosylation and/or conformation between native and recombinant proteins. We have exploited the free-living nematode Caenorhabditis elegans to examine its suitability as an alternative system for recombinant expression of parasitic nematode vaccine candidates. We focussed on Haemonchus contortus aminopeptidase H11 glycoprotein, which is enriched in a gut membrane fraction capable of inducing significant protection against this important ovine gastrointestinal nematode. We show that H. contortus H11 expressed in C. elegans is enzymatically active and MALDI mass spectrometry identifies similar di- and tri-fucosylated structures to those on native H11, with fucose at the 3- and/or 6-positions of the proximal GlcNAc. Some glycan structural differences were observed, such as lack of LDNF. Serum antibody to native H11 binds to C. elegans recombinant H11 and most of the antibody to rH11 or native H11 is directed to glycan moieties. Despite these similarities, no reduction in worm burden or faecal egg count was observed following immunisation of sheep with C. elegans-expressed recombinant H11 protein. The findings suggest that the di- and tri-fucosylated N-glycans expressed on rH11 do not contribute to the protective effect of H11 and that additional components present in native H11-enriched extract are likely required for enhancing the antibody response necessary for protection.  相似文献   
6.
Metabolic syndrome-related diseases affect millions of people worldwide. It is well established that changes in nutritional habits and lifestyle can improve or prevent metabolic-related pathologies such as type-2 diabetes and obesity. Previous reports have shown that nutritional supplements have the capacity to limit glucose intolerance and suppress diabetes development. In this study, we investigated the effect of dietary supplementation with fish-derived extracts on obesity and type 2 diabetes and their impact on gut microbial composition. We showed that nutritional supplements containing Fish Complex (FC), Fish Complex combined with Cod Powder (FC + CP), or Cod Powder combined with Collagen (CP + C) improved glucose intolerance, independent of abdominal fat accumulation, in a mouse model of diet-induced obesity and type 2 diabetes. In addition, collagen-containing supplements distinctly modulate the gut microbiome in high-fat induced obesity in mice. Our results suggest that fish-derived supplements suppress diet-induced type 2 diabetes, which may be partly mediated through changes in the gut microbiome. Thus, fish-derived supplements and particularly the ones containing fish collagen have potential beneficial properties as dietary supplements in managing type 2 diabetes and metabolic syndrome via modulation of the gut microbiome.  相似文献   
7.
Hydroponic and field experiments were conducted to assess the optimum nitrogen (N) levels in strawberry leaves for the appropriate management of its N nutrition under field or protected cultivation. Unlike the common view that leaf petiole is the right plant organ to sample for strawberries, the study showed that the leaf blade, of the most recently fully expanded leaf, is more responsive and therefore a better indicator of the N supply changes in the strawberry plant. This was attributed to the distinctive characteristic of strawberry plants to accumulate high concentrations of nitrates in leaf blades when there is luxury consumption of N.  相似文献   
8.
The computer‐assisted sperm analysis (CASA) has become a standard laboratory tool. Although it contributes a lot to the objective sperm motility assessment, its measurements may be affected by many factors. The aim of the study was to evaluate the effect of chamber on boar semen CASA results. Totally, 100 extended (30 × 106 sperm/ml) boar semen samples were analysed by CASA. Each sample was evaluated using Makler, Leja 4 chamber 20 μm and conventional glass slide/coverslip chambers (MC, LC and GSC, respectively). The differences in values between MC and LC and between MC and GSC were significantly positive (higher values for MC compared with LC and GSC) for total motility, progressive, rapid movement, VCL, VSL, VAP, STR and hyperactive, thus indicating a systematic effect. Between LC and GSC, the differences in many parameters (non‐progressive, progressive, slow, LIN, STR, hyperactive) were evenly distributed around zero, while in all other parameters the differences were significantly positive (higher values for LC compared with GSC), except for medium movement. Based on the estimated intraclass correlation coefficients, the method agreement between MC and LC and between LC and GSC was overall moderate to good, depending on the parameter; nonetheless, it was poor between MC and GSC. The limits of agreement between methods can vary considerably depending on the parameter and should be considered when comparisons between CASA measurements of different andrology laboratories or studies have to be performed.  相似文献   
9.
The assessment of soil pollution with heavy metals has been studied, based on experimental soil and plant analytical heavy metal data obtained by a pot experiment conducted during 2010?C2011 in a green house. A completely randomized block design was used, including the following sludge treatments (in tons per hectare): 0, 6, 12, 18, 24, 30, and (30+treated wastewater) in four replications. Lettuce (Lactuca sativa L.) var. longifolia was used as a test plant. Three indices were proposed, i.e., (1) elemental pollution index, (2) heavy metal load, and (3) total concentration factor. They were found to be linearly and statistically significantly related to the pollution load index, which was used as a reference index, and curvilinearly related to lettuce dry matter yield. It was concluded that the above indices could be used for the assessment of soil pollution level.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号